Practice 2



Practice 2a (Answers at the end)

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

____ 1. When methanol undergoes complete combustion, the products are carbon dioxide and water.

__ CH3OH(λ) + __ O2(g) → __ CO2(g) + __ H2O(g)

What are the respective coefficients when the equation is balanced with the smallest whole numbers?

|a. |1, 1, 1, 1 |

|b. |1, 2, 1, 2 |

|c. |2, 2, 2, 4 |

|d. |2, 3, 2, 4 |

|e. |2, 4, 6, 4 |

____ 2. Metals react with oxygen to give oxides with the general formula MxOy. Write a balanced chemical equation for the reaction of iron with oxygen to yield iron(III) oxide.

|a. |Fe(s) + O2(g) → FeO2(s) |

|b. |2 Fe(s) + 3 O2(g) → Fe2O3(s) |

|c. |3 Fe(s) + O2(g) → Fe3O2(s) |

|d. |4 Fe(s) + 3 O2(g) → 2 Fe2O3(s) |

|e. |6 Fe(s) + O2(g) → 2 Fe3O(s) |

____ 3. Calcium reacts with fluorine gas to produce calcium fluoride. How many moles of Ca will react with 1.0 moles of F2?

|a. |0.50 mol |

|b. |1.0 mol |

|c. |1.5 mol |

|d. |2.0 mol |

|e. |4.0 mol |

____ 4. Sodium carbonate reacts with hydrochloric acid as shown below in an unbalanced chemical equation. What mass of CO2 is produced from the reaction of 2.94 g Na2CO3 with excess HCl?

Na2CO3(s) + HCl(aq) → NaCl(aq) + CO2(g) + H2O(λ)

|a. |1.22 g |

|b. |2.44 g |

|c. |2.94 g |

|d. |5.88 g |

|e. |7.08 g |

____ 5. What is a correct method for determining how many grams of calcium oxide are produced in the reaction of 10.0 g calcium with excess oxygen?

2 Ca(s) + O2(g) → 2 CaO(s)

|a. |10.0 g Ca [pic][pic][pic]= |

|b. |10.0 g Ca [pic][pic][pic]= |

|c. |10.0 g Ca [pic][pic][pic]= |

|d. |10.0 g Ca [pic][pic][pic]= |

|e. |10.0 g Ca [pic][pic][pic]= |

____ 6. How many moles of potassium bromide can be produced from the reaction of 2.92 moles of potassium with 1.78 moles of bromine gas?

2 K(s) + Br2(g) → 2 KBr(s)

|a. |1.46 mol |

|b. |1.78 mol |

|c. |2.92 mol |

|d. |3.56 mol |

|e. |5.84 mol |

____ 7. Under certain conditions the formation of ammonia from nitrogen and hydrogen has a 7.82% yield. Under these conditions, how many grams of NH3 will be produced from the reaction 25.0 g N2 with 2.00 g H2?

N2(g) + 3 H2(g) → 2 NH3(g)

|a. |0.881 g |

|b. |2.37 g |

|c. |3.12 g |

|d. |11.3 g |

|e. |30.4 g |

____ 8. A mass of 2.052 g of a metal carbonate, MCO3, is heated to give the metal oxide and 0.4576 g CO2.

MCO3(s) → MO(s) + CO2(g)

What is the identity of the metal?

|a. |Cu |

|b. |Mg |

|c. |Ca |

|d. |Ba |

|e. |Co |

____ 9. A mixture of MgCO3 and MgCO3·3H2O has a mass of 3.057 g. After heating to drive off all the water the mass is 2.790 g. What is the mass percent of MgCO3·3H2O in the mixture?

|a. |22.4% |

|b. |43.2% |

|c. |67.0% |

|d. |77.6% |

|e. |91.3% |

____ 10. The combustion of 0.1703 mole of a hydrocarbon produces 12.27 g H2O and 22.48 g CO2. What is the molar mass of the hydrocarbon?

|a. |16.04 g/mol |

|b. |30.07 g/mol |

|c. |44.08 g/mol |

|d. |72.15 g/mol |

|e. |92.13 g/mol |

____ 11. Soft drink bottles are made of polyethylene terephthalate (PET), a polymer composed of carbon, hydrogen, and oxygen. If 4.375 g PET is burned in oxygen it produces 1.515 g H2O and 9.251 g CO2. What is the empirical formula for PET?

|a. |CHO |

|b. |CH7O5 |

|c. |C5H7O |

|d. |C8H10O |

|e. |C10H8O5 |

____ 12. Which of the following statements are correct?

|1. |All salts of carbonate ion are soluble in water. |

|2. |Most salts of chloride ion are soluble in water. |

|3. |All salts of hydroxide ion are soluble in water. |

|a. |1 only |

|b. |2 only |

|c. |3 only |

|d. |1 and 2 |

|e. |1, 2, and 3 |

____ 13. Which of the following compounds will be soluble in water: KNO3, Ca3(PO4)2, CuCl2, and Fe2S3?

|a. |KNO3 and Ca3(PO4)2 |

|b. |KNO3 and CuCl2 |

|c. |Ca3(PO4)2 and Fe2S3 |

|d. |CuCl2 and Fe2S3 |

|e. |KNO3, Ca3(PO4)2, and Fe2S3 |

____ 14. A white solid is either NaI or NaNO3. If an aqueous solution of the solid is prepared, the addition of which reagent will allow you to distinguish between the two compounds?

|a. |NaOH |

|b. |HCl |

|c. |K3PO4 |

|d. |NH4Br |

|e. |Pb(NO3)2 |

____ 15. What is the net ionic equation for the reaction of aqueous lead(II) nitrate with aqueous sodium bromide?

|a. |Pb(NO3)2(aq) + 2 NaBr(aq) → PbBr2(aq) + 2 NaNO3(s) |

|b. |Na+(aq) + NO3-(aq) → NaNO3(s) |

|c. |Pb2+(aq) + 2 Br-(aq) → PbBr2(s) |

|d. |Pb2+(aq) + 2 Na+(aq) → PbNa2(s) |

|e. |Pb(NO3)2(aq) + 2 NaBr(aq) → PbBr2(s) + 2 NaNO3(aq) |

____ 16. Which of the following compounds is a weak acid?

|a. |H3PO4 |

|b. |HI |

|c. |HBr |

|d. |HClO4 |

|e. |H2SO4 |

____ 17. Which of the following compounds is a weak base?

|a. |LiOH |

|b. |KCl |

|c. |CH3CO2H |

|d. |Sr(OH)2 |

|e. |NH3 |

____ 18. Which of the following species are strong acids: HNO3, HBr, H3PO4,CH3CO2H, and HSO4-?

|a. |HNO3 and HBr |

|b. |HNO3 and H3PO4 |

|c. |HBr and HSO4- |

|d. |H3PO4, CH3CO2H, and HSO4- |

|e. |HNO3, H3PO4, and HSO4- |

____ 19. Sulfuric acid is the product of the reaction of ____ and H2O.

|a. |H2S |

|b. |SO2 |

|c. |SO32- |

|d. |SO42- |

|e. |SO3 |

____ 20. Metal oxides react with water to produce ____.

|a. |hydrogen gas |

|b. |bases |

|c. |oxygen gas |

|d. |acids |

|e. |reduced metals |

____ 21. What is the net ionic equation for the reaction of aqueous lithium hydroxide and aqueous nitric acid?

|a. |H+(aq) + LiOH(aq) → H2O(λ) + Li+(aq) |

|b. |H+(aq) + OH-(aq) → H2O(λ) |

|c. |HNO3(aq) + LiOH(aq) → H2O(λ) + LiNO3(aq) |

|d. |Li+(aq) + NO3-(aq) → LiNO3(aq) |

|e. |LiOH(aq) + H2O(λ) → H+(aq) + Li(OH)2(s) |

____ 22. What are the spectator ions in the reaction between aqueous perchloric acid and aqueous potassium hydroxide?

|a. |H+, ClO4-, K+, and OH- |

|b. |H+ and OH- |

|c. |K+ and ClO4- |

|d. |H+ and ClO4- |

|e. |K+ and OH- |

____ 23. Write a net ionic equation for the reaction of aqueous acetic acid and aqueous potassium hydroxide.

|a. |CH3CO2H(aq) + KOH(aq) → K+(aq) + CH3CO2-(aq) + H2O(λ) |

|b. |CH3CO2H(aq) + KOH(aq) → KCH3CO2(aq) + H2O(λ) |

|c. |H+(aq) + OH-(aq) → H2O(λ) |

|d. |CH3CO2H(aq) + OH-(aq) → CH3CO3H2-(aq) |

|e. |CH3CO2H(aq) + OH-(aq) → CH3CO2-(aq) + H2O(λ) |

____ 24. One use of calcium oxide (lime) is in pollution control at coal-burning power plants. Which reaction below occurs in the smokestack of a power plant?

|a. |CaO(s) + C(s) → Ca(s) + CO(g) |

|b. |CaO(s) + SO3(g) → CaSO4(s) |

|c. |CaO(s) + SO3(g) → CaS(s) + 2 O2(g) |

|d. |2 CaO(s) + C(s) → Ca2C(s) + O2(g) |

|e. |CaO(s) + SO3(g) → Ca(s) + SO2(g) + O2(g) |

____ 25. Write a net ionic equation for the reaction of limestone and a strong acid.

|a. |Ca(s) + 2 H+(aq) → Ca2+(aq) + H2(g) |

|b. |CaCO3(s) + 2 H+(aq) → Ca2+(aq) + H2CO3(s) |

|c. |CaCO3(s) + 2 HCl(aq) → CaCl2(aq) + H2CO3(aq) |

|d. |CaCO3(s) + 2 H+(aq) → Ca2+(aq) + CO2(g) + H2O( λ) |

|e. |CaO(s) + 2 H+(aq) → Ca2+(aq) + H2O( λ) |

____ 26. Write a balanced equation for the reaction of aqueous solutions of baking soda and acetic acid.

|a. |NaHCO3(aq) + CH3CO2H(aq) → NaCH3CO2(aq) + H2O( λ) + CO2(g) |

|b. |2 NaHCO3(aq) + CH3CO2H(aq) → 2 Na2CO3(aq) + CH4(aq) + 2H2O( λ) + CO2(g) |

|c. |NaHCO3(aq) + CH3CO2H(aq) → H2CO3(s) + NaCH3CO2(aq) |

|d. |NaHCO3(aq) + CH3CO2H(aq) → NaOH(aq) + CH3CO2H(aq) + CO2(g) |

|e. |NaHCO3(aq) + CH3CO2H(aq) → CH4(aq) + 2 CO2(g) + O2(g) + NaOH(aq) |

____ 27. Write a balanced equation for the reaction of aqueous solutions of potassium sulfide and hydrochloric acid.

|a. |K2S(aq) + 2 HCl(aq) → 2 KH(aq) + SCl2(g) |

|b. |K2S(aq) + HCl(aq) → HS(g) + KCl(aq) |

|c. |K2S(aq) + 2 HCl(aq) → H2S(g) + 2 KCl(aq) |

|d. |K2S(aq) + 2 HCl(aq) → 2 K(s) + H2(g) + SCl2(g) |

|e. |K2S(aq) + 2 HCl(aq) → S(s) + H2(g) + 2 KCl(aq) |

____ 28. Which of the following chemical equations is an acid-base reaction?

|a. |2 HCl(aq) + Zn(s) → H2(g) + ZnCl2(aq) |

|b. |HCl(aq) + NH3(aq) → NH4Cl(aq) |

|c. |HCl(aq) + AgNO3(aq) → AgCl(s) + HNO3(aq) |

|d. |Ba(OH)2(aq) + Na2SO4(aq) → BaSO4(s) + 2 NaOH(aq) |

|e. |2 NaOH(aq) + CuCl2(aq) → Cu(OH)2(s) + 2 NaCl(aq) |

____ 29. Which molecule in the reaction below undergoes oxidation?

2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g)

|a. |C2H2 |

|b. |O2 |

|c. |H2O |

|d. |CO2 |

|e. |C2H2 and O2 |

____ 30. Which species in the reaction below undergoes reduction?

Sn(s) + 2 H+(aq) → Sn2+(aq) + H2(g)

|a. |Sn |

|b. |H+ |

|c. |Sn2+ |

|d. |H2 |

|e. |No compound is reduced. |

____ 31. Which compound is the oxidizing agent in the reaction below?

I-(aq) + ClO-(aq) → IO-(aq) + Cl-(aq)

|a. |I- |

|b. |H2O |

|c. |Cl- |

|d. |IO- |

|e. |ClO- |

____ 32. How many liters of 0.1107 M KCl(aq) contain 15.00 g of KCl?

|a. |0.02227 L |

|b. |0.5502 L |

|c. |1.661 L |

|d. |1.818 L |

|e. |123.8 L |

____ 33. If 0.3000 g of impure soda ash (Na2CO3) is titrated with 17.66 mL of 0.1187 M HCl, what is the percent purity of the soda ash?

Na2CO3(aq) + 2 HCl(aq) → 2 NaCl(aq) + H2O(λ) + CO2(g)

|a. |11.11% |

|b. |22.22% |

|c. |57.91% |

|d. |37.03% |

|e. |74.06% |

____ 34. Which one of the following statements is INCORRECT?

|a. |In an exothermic process heat is transferred from the system to the surroundings. |

|b. |The greater the heat capacity of an object, the more thermal energy it can store. |

|c. |The SI unit of specific heat capacity is joules per gram per Kelvin. |

|d. |The specific heat capacity has a positive value for liquids and a negative value for gases. |

|e. |When heat is transferred from the system to the surroundings, q is negative. |

____ 35. How much energy is required to change the temperature of 21.5 g Cu from 27.0 °C to 88.1 °C? The specific heat capacity of copper is 0.385 J/g·K.

|a. |223 J |

|b. |506 J |

|c. |641 J |

|d. |729 J |

|e. |3.41 × 103 J |

____ 36. When 27.0 g of an unknown metal at 88.4 °C is placed in 115 g H2O at 21.0 °C, the final temperature of the water is 23.7 °C. What is the specific heat capacity of the metal? The specific heat capacity of water is 4.184 J/g·K.

|a. |0.34 J/g·K |

|b. |0.51 J/g·K |

|c. |0.74 J/g·K |

|d. |0.94J/g·K |

|e. |1.4 J/g·K |

____ 37. Calculate the amount of heat required to change 50.0 g ice at -20.0 °C to steam at 135 °C. (Heat of fusion = 333 J/g; heat of vaporization = 2260 J/g; specific heat capacities: ice = 2.09 J/g·K, liquid water = 4.18 J/g·K, steam = 1.84 J/g·K)

|a. |4.18 kJ |

|b. |32.4 kJ |

|c. |78.8 kJ |

|d. |135 kJ |

|e. |156 kJ |

____ 38. Calculate ΔE for the system in which a gas absorbs 31 J of heat and does 18 J of work on the surroundings?

|a. |-49 J |

|b. |-13 J |

|c. |+13 J |

|d. |+31 J |

|e. |+49 J |

____ 39. The thermochemical equation for the combustion of butane is shown below.

C4H10(g) + 13/2 O2(g) → 4 CO2(g) + 5 H2O(λ) ΔH° = -2877 kJ

What is the enthalpy change for the following reaction?

16 CO2(g) + 20 H2O(λ) → 4 C4H10(g) + 26 O2(g)

|a. |-5754 kJ |

|b. |-719.2 kJ |

|c. |+719.2 kJ |

|d. |+5754 kJ |

|e. |+1.151 × 104 kJ |

____ 40. If 1.86 g MgO is combined with 100.0 mL of 1.00 M HCl (density 100.0 g/mL) in a coffee cup calorimeter, the temperature of the resulting solution increases from 21.3 °C to 35.7 °C. Calculate the enthalpy change for the reaction per mole of MgO. Assume that the specific heat capacity of the solution is 4.18 J/g·K.

|a. |-6.13 kJ |

|b. |-28.3 kJ |

|c. |-133 kJ |

|d. |-329 kJ |

|e. |-613 kJ |

____ 41. Calculate ΔH for the following reaction,

CaO(s) + CO2(g) → CaCO3(s)

given the thermochemical equations below.

2 Ca(s) + O2(g) → 2 CaO(s) ΔH = -1270.2 kJ

C(s) + O2(g) → CO2(g) ΔH = -393.5 kJ

2 Ca(s) + 2 C(s) + 3 O2(g) → 2 CaCO3(s) ΔH = -2413.8 kJ

|a. |-4077.3 kJ |

|b. |-750.1 kJ |

|c. |-178.3 kJ |

|d. |+350.2 kJ |

|e. |+2870.6 kJ |

____ 42. Which of the following chemical equations corresponds to the standard molar enthalpy of formation of N2O?

|a. |NO(g) + 1/2 N2(g) → N2O(g) |

|b. |N2(g) + 1/2 O2(g) → N2O(g) |

|c. |2N(g) + O(g) → N2O(g) |

|d. |N2(g) + O(g) → N2O(g) |

|e. |2 N2(g) + O2(g) → 2 N2O(g) |

____ 43. Calculate [pic] for the combustion of gaseous ethanol,

C2H5OH(g) + 3 O2(g) → 2 CO2(g) + 3 H2O(g)

using standard molar enthalpies of formation.

|molecule |[pic] (kJ/mol) |

|C2H5OH(g) |-235.3 |

|CO2(g) |-393.5 |

|H2O(g) |-241.8 |

|a. |-1747.7 kJ |

|b. |-1277.1 kJ |

|c. |-793.5 kJ |

|d. |-400.0 kJ |

|e. |-83.6 kJ |

____ 44. The standard enthalpy change for the combustion of 1 mole of benzene is -3267.4 kJ.

C6H6(λ) + 15/2 O2(g) → 6 CO2(g) + 3 H2O(λ)

Calculate [pic] for benzene based on the following standard molar enthalpies of formation.

|molecule |[pic] (kJ/mol) |

|CO2(g) |-393.5 |

|H2O(λ) |-285.8 |

|a. |-6485.8 kJ |

|b. |-3946.7 kJ |

|c. |-3218.4 kJ |

|d. |+49.0 kJ |

|e. |+2588.1 kJ |

____ 45. The standard molar enthalpy of formation of NH3(g) is -45.9 kJ/mol. What is the enthalpy change if 5.38 g N2(s) and 3.32 g H2(g) react to produce NH3(g)?

|a. |-75.6 kJ |

|b. |-50.4 kJ |

|c. |-17.6 kJ |

|d. |-8.81 kJ |

|e. |-1.20 kJ |

Practice 2a Answer Section

1. ANS: D OBJ: 4.2 Balancing Chemical Equations

2. ANS: D OBJ: 4.2 Balancing Chemical Equations

3. ANS: B OBJ: 4.3 Mass Relationships in Chemical Reactions: Stoichiometry

4. ANS: A OBJ: 4.3 Mass Relationships in Chemical Reactions: Stoichiometry

5. ANS: E OBJ: 4.3 Mass Relationships in Chemical Reactions: Stoichiometry

6. ANS: C OBJ: 4.4 Reactions in which One Reactant is Present in Limited Supply

7. ANS: B OBJ: 4.5 Percent Yield

8. ANS: D OBJ: 4.6 Chemical Equations and Chemical Analysis

9. ANS: A OBJ: 4.6 Chemical Equations and Chemical Analysis

10. ANS: C OBJ: 4.6 Chemical Equations and Chemical Analysis

11. ANS: E OBJ: 4.6 Chemical Equations and Chemical Analysis

12. ANS: B OBJ: 5.1 Properties of Compounds in Aqueous Solution

13. ANS: B OBJ: 5.1 Properties of Compounds in Aqueous Solution

14. ANS: E OBJ: 5.2 Precipitation Reactions

15. ANS: C OBJ: 5.2 Precipitation Reactions

16. ANS: A OBJ: 5.3 Acids and Bases

17. ANS: E OBJ: 5.3 Acids and Bases

18. ANS: A OBJ: 5.3 Acids and Bases

19. ANS: E OBJ: 5.3 Acids and Bases

20. ANS: B OBJ: 5.3 Acids and Bases

21. ANS: B OBJ: 5.4 Reactions of Acids and Bases

22. ANS: C OBJ: 5.4 Reactions of Acids and Bases

23. ANS: E OBJ: 5.4 Reactions of Acids and Bases

24. ANS: B OBJ: 5.4 Reactions of Acids and Bases

25. ANS: D OBJ: 5.5 Gas-Forming Reactions

26. ANS: A OBJ: 5.5 Gas-Forming Reactions

27. ANS: C OBJ: 5.5 Gas-Forming Reactions

28. ANS: B OBJ: 5.6 Classifying Reactions in Aqueous Solution

29. ANS: A OBJ: 5.7 Oxidation-Reduction Reactions

30. ANS: B OBJ: 5.7 Oxidation-Reduction Reactions

31. ANS: E OBJ: 5.7 Oxidation-Reduction Reactions

32. ANS: D OBJ: 5.8 Measuring Concentrations of Compounds in Solution

33. ANS: D OBJ: 5.10 Stoichiometry of Reactions in Aqueous Solution

34. ANS: D OBJ: 6.2 Specific Heat Capacity and Heat Transfer

35. ANS: B OBJ: 6.2 Specific Heat Capacity and Heat Transfer

36. ANS: C OBJ: 6.2 Specific Heat Capacity and Heat Transfer

37. ANS: E OBJ: 6.3 Energy and Changes of State

38. ANS: C OBJ: 6.4 The First Law of Thermodynamics

39. ANS: E OBJ: 6.5 Enthalpy Changes for Chemical Reactions

40. ANS: C OBJ: 6.5 Calorimetry

41. ANS: C OBJ: 6.7 Hess's Law

42. ANS: B OBJ: 6.8 Standard Enthalpies of Formation

43. ANS: B OBJ: 6.8 Standard Enthalpies of Formation

44. ANS: D OBJ: 6.8 Standard Enthalpies of Formation

45. ANS: C OBJ: 6.8 Standard Enthalpies of Formation

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